Google released Google Universal Search in mid May 2007 which saw the integration of all its various search verticals including Google Maps, Google Images and Google Video into the main web results.
Although Google Universal Search has only been around for under a month, early results from a recent study by Hitwise show the biggest winners from this enhancement were Google Maps with a 20.34 % boost in traffic and Youtube with an 8.26% increase in traffic.
Percentage U.S. Visits to Custom Category of Top Google Properties
I believe that traffic to Google Maps will continue its fantastic growth in the future as more enhancements like Google Street View are introduced and local search continues its growth.